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By Jihyun Byun, Undergraduate, Public Health, University of Texas at Austin

Antibiotic resistance has become an increasingly urgent public health issue as strains of resistant bacteria crop up more and more frequently, posing serious challenges for healthcare professionals and their patients. Although this problem is multifaceted, it seems to me that it is most often blamed from a policy perspective: overuse in livestock, unnecessary prescriptions, lack of regulations in developing countries, etc.

Dr. Gautam Dantas’ work, presented by graduate student Alaric D’Souza, approaches antibiotic resistance from a different angle: In the environment, how are resistance genes exchanged between pathogens and harmless microbes? This question becomes even more intriguing within a setting such as Peru and El Salvador, developing countries that have poorer communities.

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Because many rural residents come in direct contact with livestock, soil, and other environmental reservoirs and also lack industrialized waste management infrastructure, it’s been found that antibiotic resistance exchange happens much more easily than in developing countries. These exchanges most often happen in the soil, where they may be disseminated into the water supply.

Dr. Dantas’ work draws from samples taken from humans, animals, and sewage samples, and the figure below illustrates an important finding from them: the various antibiotic resistance genes and their associations, or lack thereof, to a specific source. For example, Alaric pointed out that genes that correspond to a common mechanism for antibiotic resistance, drug efflux pumps (in which the organism develops a mechanism to pump the antibiotic out of itself) aren’t clustered to one source – rather, the blue squares are scattered throughout the figure, suggesting that efflux pump genes were found within a wide array of metagenomes.

In conclusion, studying how the environment contributes to antibiotic resistance through the exchange of resistance genes can provide public health scientists with a greater array of tools as they identify “high-risk environments” and design novel, more targeted approaches.